Thermal infrared cameras (e.g. cameras that image wavelengths in the range of three to fourteen micrometers) are well known and employed in a wide variety of applications. A typical thermal infrared camera, often referred to simply as an infrared camera or IR camera, uses an infrared detector to detect infrared energy that is provided to the infrared detector through the infrared camera's lens. The infrared camera may also include a display for a user to view images generated by the infrared camera based on the infrared energy, or the images may be stored by the infrared camera or transmitted (e.g., via a wireless or wired network) for remote viewing and/or storage.
When designed for outdoor use, for example, the infrared camera may be manufactured to be weatherproof, with for example weatherproof seals and tight manufacturing tolerances between housing components, which may significantly increase manufacturing costs. Alternatively, an infrared-transmissive window may be used to form one side of an enclosure to protect the infrared camera and through which the infrared camera may receive infrared energy to generate images for storing and/or viewing by a user on a display. However, the infrared-transmissive window is typically made of expensive materials (e.g., germanium), which may be fragile and easily damaged and add significantly to the cost of the infrared camera system.
Other conventional, less expensive infrared-transmissive windows exist (e.g., made of conventional high density polyethylene or other polymer materials) for passive infrared (PIR) motion detection applications. However, these conventional polymer materials typically have strong absorptions that limit infrared transmission and other undesirable properties (e.g., non-uniformities, excessive thicknesses, and inadequate structural integrity at desired dimensions), which make these conventional polymer materials unsuitable for thermal infrared imaging applications.
As a result, there is a need for infrared-transmissive materials and techniques, which for example may be suitable for providing a dome for thermal infrared camera imaging applications.